Update README

plugins/cargo/README.md

 # cargo
 
-This plugin adds completion for the Rust build tool [`cargo`](https://github.com/rust-lang/cargo).
+This plugin adds completion for the Rust build tool [`Cargo`](https://github.com/rust-lang/cargo).
 
 To use it, add `cargo` to the plugins array in your zshrc file:
 
@@ -8,4 +8,4 @@ To use it, add `cargo` to the plugins array in your zshrc file:
 plugins=(... cargo)
 ```
 
-Updated on October 4th, 2016.
+Updated on March 3rd, 2019, from [Cargo 0.34.0](https://github.com/rust-lang/cargo/releases/tag/0.34.0).